Lab: The base keyword

Objective

In this lab exercise, we will delve into the functionality of the base keyword. Our goal is to understand how base can be used to access members of a base class from within a derived class. This is a fundamental concept in object oriented programming, particularly when dealing with inheritance and method overriding.

Provided Code

Carefully review the provided code. Notice that it defines a class called Shape with properties for position (X, Y) and size (Width, Height). The Print method displays these properties. In this lab we will write classes that inherit from Shape and override the Print method.

class Shape
{
    public int X { get; set; } = 0;
    public int Y { get; set; } = 0;
    public int Width { get; set; } = 1;
    public int Height { get; set; } = 1;

    public virtual void Print()
    {
        Console.WriteLine($"Position:\t ({X}, {Y})");
        Console.WriteLine($"Size:\t\t {Width} x {Height}");
    }
}

The below script needs to be able to find the current output cell; this is an easy method to get it.

Instructions

Step 1: Implement the Star Class

Start by implementing the Star class. This class should inherit from Shape and include an additional property called NumberOfPoints. When you’re done, you should be able to run the following code:

new Star()
{
    X = 12,
    Y = 3,
    Width = 20,
    Height = 18,
    NumberOfPoints = 5
}.Print();

Position:	 (12, 3)

Size:		 20 x 18

Points:		 5

new Star() { NumberOfPoints = 8 }.Print();

Position:	 (0, 0)

Size:		 1 x 1

Points:		 8

Important

You should not have to duplicate Shape’s implementation of Print in its subclasses.

🤔 Reflection

How does using the base keyword in the Star class’s Print method simplify your code and maintain consistency with the Shape class?

Step 2: Implement the Ellipse Class

Now, let’s implement the Ellipse class. This class should also inherit from Shape. It should calculate and display the major and minor axes based on its width and height. Once completed, you should be able to run the following example:

new Ellipse()
{
    X = 12,
    Y = 3,
    Width = 20,
    Height = 18
}.Print();

Position:	 (12, 3)

Size:		 20 x 18

Major axis:	 20

Minor axis:	 18

new Ellipse() { Width = 50, Height = 100 }.Print();

Position:	 (0, 0)

Size:		 50 x 100

Major axis:	 100

Minor axis:	 50

Conclusion

Simple enough. Good job. Let’s keep exploring. 🔎